1. Field of the Invention
This specification relates to various embodiments of an apparatus and a method for estimating an initial position of a rotor of a motor.
2. Background of the Invention
Generally, a permanent magnet synchronous machine (PMSM) has been mainly used in a high performance servo application field, due to its high efficiency, its high torque and output per unitary volume, and its rapid dynamic characteristic. Since a magnetic flux of a rotor of the PMSM is generated from a permanent magnet attached to the rotor, it is necessary to correctly detect an absolute position of the magnetic flux generated from the permanent magnet, that is, an absolute position of the rotor, for precise and instantaneous control of a torque generated from the motor. Thus, absolute position information of the rotor is obtained from an absolute position detector for detecting an absolute position of the rotor, at the time of controlling the PMSM, thereby being used to perform a magnetic flux-oriented control.
However, an absolute type encoder for detecting an absolute position is more expensive than an incremental type encoder for detecting a relative position. Thus, in an industry field, such an incremental encoder is mainly preferred. In case of driving the PMSM in an industry field using an incremental encoder, an initial position of a rotor should be necessarily estimated.